Tissue repair system

ABSTRACT

A repair system including a closure prosthesis and deployment device, and associated methods for repairing any imperfection including a flaw, hole, tear, bulge, or, in some cases, a deliberate cut or incision in any tissue including an intervertebral disc. The prosthesis has first and second side portions with a connecting central portion, and is designed to span an imperfection with opposite ends positioned on opposite sides of the imperfection. The prosthesis may include anchoring features including barbs and/or members that extend transversely. The deployment device can include a canula for positioning the prosthesis near the imperfection, and, in some cases, a mechanism that may cause the two sides of the prosthesis to be deployed in a specific order.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates generally to medical devices, and moreparticularly, to medical devices for repair of tissue, includingintervertebral discs.

2. Description of Related Art

The spinal cord is the body's main nerve pathway, extending from thebase of the skull down the back toward the lower (sacral) region of theback, where it branches. The spinal cord is protected from injury anddamage by the vertebral column, a flexible column comprised of bonescalled vertebrae, which encircle and enclose the spinal column. Most ofthe vertebrae in the spinal column are interspersed with intervertebraldiscs, which are compliant discs, each approximately 1.0 cm to 1.5 cmthick. The discs are disposed between adjacent vertebrae in the spinalcolumn and allow limited motion and rotation between those adjacentvertebrae. The cumulative effect of the motion provided by the discallows the spinal column to flex and move. The discs also act as shockabsorbers. The intervertebral discs themselves are comprised of arelatively tough outer layer called the nucleus purposus 222, inside ofwhich is a soft, gel-like center called the nucleus purposus 224.

FIG. 1 is a plan view of a single vertebra, shown generally at 200, andits associated intervertebral disc 202. (The anatomy shown in FIG. 1 isgenerally that of a lumbar vertebra, although the anatomy of thoracicand lumbar vertebra is similar; therefore, FIG. 1 can be considered toillustrate the basic principles of both thoracic and lumbar vertebralanatomy.) The spinous process 206 of the vertebra 200 extends dorsallyand can typically be palpated and felt through the skin of the back.Also in the dorsally-extending portion of the vertebra 200 are twotransverse processes 208 and two mammillary processes and facet joints212. A spinal canal 214 (i.e., an opening) is provided in the vertebra200. The spinal cord and nerves 216 extend through the spinal canal 214such that the spinal cord 216 receives the full protection of the bony,dorsally-located spinous, transverse, and mammillary processes and facetjoints 206, 208, 212. The vertebral body also protects the spinal cordand nerves 216 ventrally. Periodically, nerves 218 branch out from thespinal cord 216 to innervate various areas of the body. The forward orventral edge of the vertebral foramen 221 (see FIGS. 1 and 2) is definedby the vertebral body (not shown in FIG. 1), a bony, generallyelliptical shelf in front of which the intervertebral disc 202 rests.FIG. 1 also illustrates the basic structure of the intervertebral disc202, including the nucleus purposus 222 and the nucleus pulposus 224.

The vertebrae and the intervertebral discs are usually in goodalignment, e.g., as shown in FIG. 1, and the intervertebral discsnormally perform their function without incident. However, there arecertain conditions, notably traumatic injury and vertebral columndegeneration, that can cause problems. For example, if a weak spotdevelops in the nucleus purposus, the pressure on the disc may cause thenucleus purposus 224 to be pushed through the weak spot, a conditioncalled herniation. This reduces the shock-absorbing ability of the disc,and may impinge on spinal or surrounding nerves, causing pain andpossibly sensory or motor problems. Moreover, trauma may cause anintervertebral disc to fail entirely, potentially causing all of theabove problems, even if a particular weak spot in the nucleus purposushas not developed.

FIG. 2 is a plan view similar to that of FIG. 1, illustrating aherniated or traumatized intervertebral disc 202. As shown, the nucleuspulposus 224 is protruding from the intervertebral disc 202 through acut or flaw 204 in the intervertebral disc 202. The protruding nucleuspulposus 224 impinges on one of the exiting nerves 218 as well as thespinal cord 216 or cauda equina.

If an intervertebral disc has failed or become herniated, a typicalcorrection is a surgical procedure to remove some or all of theherniated portion (or the protruding nucleus purposus 224) but noattempt is made to repair the nucleus purposus by surgically closing anyhole or incision. FIG. 3 is a plan view similar to that of FIG. 1showing partial results of a typical repair procedure in which theprotruding nucleus pulposus 224 is removed and, depending on theprocedure, the cut, incision, tear, or flaw 204 may be altered orneatened so as to provide for easier closure. In the view of FIG. 3, thecut, incision, tear, or flaw 204 is still open.

Any surgery to the vertebral column can be traumatic for the patient,and, depending on the area of the intervertebral column that is to berepaired, it can be difficult to access the area to make repairs. It isvery difficult to close the nucleus purposus effectively; therefore noattempt is currently made to close or repair this defect.

SUMMARY OF THE INVENTION

One aspect of the invention relates to a method for repairing animperfection in a disc associated with a spinal column. The term,“imperfection” refers to any irregularity including a flaw, hole, tear,bulge, or, in some cases, a deliberate cut or incision. The methodcomprises inserting a first end portion of a prosthesis into a firstportion of the disc. The prosthesis has a central portion connected tothe first end portion and a second end portion connected to the centralportion. The first end portion of the prosthesis has a first anchoringdevice and the second end portion of the prosthesis has a secondanchoring device. The first end portion of the prosthesis is associatedwith first portion of the disc that is on a first side of the cut. Themethod also comprises associating the second end portion of theprosthesis into a second portion of the disc that is circumferentiallyspaced from the first portion of the disc. The second portion of thedisc is on a second side of the cut. The central portion of theprosthesis spans the cut and inserting the second end of the prosthesisfarther into the disc draws the first side of the cut closer to thesecond side of the cut.

In some embodiments, the first anchor may include at least oneprojection extending away from the first end portion. The second anchormay include at least one barb. The prosthesis, in an installed position,may provide a circumferential force on the disc. The prosthesis mayprovide a hoop stress on the disc. The prosthesis may help to maintainor help to increase the axial height of the disc. The prosthesis mayhelp to close the cut on the disc, and may also help to maintain nucleusmaterial within the disc. It is also possible to provide an optionaladditional prosthesis in roughly the same location as the previousprosthesis. This additional prosthesis can be disposed at an angledifferent than the angle of the previous prosthesis. In some cases, theadditional prosthesis can be vertically disposed.

In another aspect, the invention can be used on any imperfection of anytissue.

In another aspect, the invention is used to join two different types oftissue.

Another aspect of the invention relates to a system configured todeliver a prosthesis to a disc of a mammal. The system comprises a firstpenetrating member carrying a first portion of the prosthesis, and asecond penetrating member spaced from the first penetrating member andcarrying a second portion of the prosthesis. A first rod is associatedwith the first penetrating member and is configured to move the firstportion of the prosthesis with respect to the first penetrating member.A second rod is associated with the second penetrating member and isconfigured to move the second portion of the prosthesis with respect tothe second penetrating member. Motion of the first rod is capable ofejecting the first portion of the prosthesis from the first penetratingmember, and motion of the second rod is capable of ejecting the secondportion of the prosthesis from the second penetrating member.

In another aspect, the second rod may have a range of motion greaterthan or equal to that of the first rod.

In another aspect, the first penetrating member may be disposedcoaxially outward of the first rod and the second penetrating member maybe disposed coaxially outward of the second rod.

In another aspect, the first penetrating member and the secondpenetrating member may both be associated with a pushing member.

In another aspect, the pushing member may be associated with a firsttrigger, such that motion of the first trigger moves the pushing member.The first rod may be connected to a first follower, the first followerinteracting with a first cam.

In another aspect, the second rod may be connected to a second follower,the second follower interacting with a second cam.

In another aspect, the first cam and the second cam may be associatedwith a second trigger, such that motion of the second trigger moves thefirst cam and the second cam.

In another aspect, the first cam may be shaped differently from thesecond cam, and the different shapes of the first cam and the second cammay cause the first follower to move differently than the secondfollower.

In another aspect, the first follower may move a first predetermineddistance and then cease to move after achieving the first predetermineddistance. In some cases, the first predetermined distance mayapproximate half of a length of a first anchor associated with the firstend portion. In some cases, the second follower may move farther thanthe first follower.

In another aspect, the first penetrating member may include a firstgroove, and the first end portion of the prosthesis may be disposed inthe first groove. The second penetrating member may include a secondgroove and the second end portion of the prosthesis may be disposed inthe second groove.

In another aspect, the first rod may be disposed in the first groove andmay engage the first end portion of the prosthesis disposed in the firstgroove. The second rod may be disposed in the second groove and mayengage the second end portion of the prosthesis disposed in the secondgroove.

Other systems, methods, features and advantages of the invention willbe, or will become, apparent to one with skill in the art uponexamination of the following figures and detailed description. It isintended that all such additional systems, methods, features andadvantages be included within this description, be within the scope ofthe invention, and be protected by the following claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be better understood with reference to the followingdrawings and description. The components in the figures are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the invention. Moreover, in the figures, likereference numerals designate corresponding parts throughout thedifferent views.

FIG. 1 is a plan view of a single vertebra and its associatedintervertebral disc, illustrating the relevant anatomical structures;

FIG. 2 is a plan view similar to that of FIG. 1, illustrating aherniated or traumatized intervertebral disc;

FIG. 3 is a plan view similar to that of FIG. 1, illustrating aherniated or traumatized disc after removal of nucleus pulposusmaterial;

FIG. 4 is a plan view of a single vertebra and an associatedintervertebral disc having a cut, tear, incision, hole or flaw,illustrating a closure prosthesis according to an embodiment of theinvention in association with the intervertebral disc;

FIG. 5 is a plan view similar to that of FIG. 4, illustrating theclosure prosthesis in position within the intervertebral disc to closethe cut, tear, incision, hole, or flaw in the intervertebral disc;

FIG. 6 is a perspective view of the closure prosthesis of FIGS. 4 and 5;

FIG. 7 is a perspective view of one embodiment of a deployment devicethat may be used to deploy the closure prosthesis of FIG. 4-6;

FIG. 8 is a cut-away perspective view of the device of FIG. 7illustrating its components;

FIG. 9 is a cut-away perspective view similar to FIG. 8 showing thedeployment device after actuation of a first trigger mechanism;

FIGS. 10 and 11 are cut-away perspective views similar to FIG. 8 showingthe deployment device after actuation of a second trigger mechanism,illustrating a sequence of motions produced by the second triggermechanism and its associated structures;

FIG. 12 is a sectional view of a vertebral column, illustrating avertebra associated with a cut intervertebral disc, and showing one endof the deployment device of FIG. 7 in cross-section, positioned toinstall the closure prosthesis of FIG. 6;

FIGS. 13-16 are sectional views similar to FIG. 12, illustrating thesequence of movements with which the closure prosthesis of FIG. 6 isinstalled;

FIG. 17 is a side elevational view of the cams associated with thesecond trigger mechanism and their associated followers, illustratingthe interaction of the cams with the followers;

FIG. 18 is a sectional view taken through Line 18-18 of FIG. 17illustrating a portion of a motion re-setting mechanism in thedeployment device;

FIGS. 19-21 are partial perspective views of the forward end of thedeployment device, illustrating the attachment of the first triggermechanism to its associated components in a sequence of operationalpositions;

FIGS. 22-25 are perspective views illustrating the cams and followersassociated with the second trigger mechanism in isolation, showing thesequence of motion in the cams and followers following actuation of thesecond trigger mechanism and illustrating schematically the positions ofthe ends of push rods coupled to the followers;

FIGS. 26-29 are perspective views illustrating another embodiment of thecams and followers associated with the second trigger mechanism inisolation, showing the sequence of motion in the cams and followersfollowing actuation of the second trigger mechanism and illustratingschematically the positions of the ends of push rods coupled to thefollowers;

FIG. 30 is a perspective view of a single vertebra and its associatedintervertebral disc, illustrating a box-shaped incision in theintervertebral disc;

FIG. 31 is a perspective view similar to that of FIG. 30, illustrating asingle, horizontally-oriented closure prosthesis closing the incision inthe intervertebral disc;

FIG. 32 is a perspective view similar to that of FIG. 30, illustrating asecond, vertically-oriented closure prosthesis closing the incision inthe intervertebral disc;

FIG. 33 is a perspective view of a single vertebra and its associatedintervertebral disc, illustrating an X-shaped incision in theintervertebral disc;

FIG. 34 is a perspective view similar to that of FIG. 33, illustrating asingle, horizontally-oriented closure prosthesis closing the incision inthe intervertebral disc;

FIG. 35 is a perspective view similar to that of FIG. 33, illustrating asecond, vertically-oriented closure prosthesis closing the incision inthe intervertebral disc;

FIG. 36 is a perspective view similar to that of FIG. 30, illustratingtwo horizontally-oriented closure prostheses closing an incision in anintervertebral disc;

FIG. 37 is a perspective view of an embodiment of a closure prosthesiswith two barbed ends; and

FIG. 38 is a perspective view of an embodiment of a closure prosthesiswith two transverse ends.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 4-6 illustrate one embodiment of a closure prosthesis 100 that isadapted to close a flaw, imperfection, cut, incision, hole, or tear inan intervertebral disc 202. Specifically, FIGS. 4 and 5 are plan viewsof a single vertebra 200 and its associated intervertebral disc 202,illustrating the association of the closure prosthesis 100 with anintervertebral disc 202, and FIG. 6 is a perspective view illustratingthe closure prosthesis 100 in isolation.

Although one particular embodiment of the closure prosthesis 100 isillustrated in those figures, the size, shape, and other characteristicsof the closure prosthesis 100 may be determined based on a number offactors, potentially including the size and shape of the imperfection;the condition and type of tissue into which the closure prosthesis 100is to be deployed; and the type and amount of circumferential or otherstress that is to be exerted by the closure prosthesis 100 on thesurrounding tissue. Recall that the term “imperfection” refers to anyirregularity including a flaw, hole, tear, bulge, or, in some cases, adeliberate cut or incision.

The closure prosthesis 100 of FIGS. 4-6 has first and second portions102, 104 with a connecting central portion 106 between first portion 102and second portion 104. As shown in FIGS. 4 and 5, closure prosthesis100 is adapted to be associated with an intervertebral disc 202 suchthat its first and second portions 102, 104 are arranged on either sideof the cut or incision 204 in the disc 202. Some embodiments includeprovisions for closing the cut or incision 204. Once in place, closureprosthesis 100 can apply a circumferential hoop stress to theintervertebral disc 202 proximate the cut or incision 204 and canimprove the axial loading characteristics of the intervertebral disc202. Closure prosthesis 100, by cinching together intervertebral disc204, may also increase the axial height of the disc.

The first portion 102 of the closure prosthesis 100 has a relativelypointed end 108 that extends generally away from central portion 106.Along the length of the first portion 102 behind the pointed end 108 arenumber of projections 112 that extend inwardly and rearwardly, such thattheir free ends generally point toward central portion 106 of closureprosthesis 100. Although only a few projections 112 are shown in FIG. 6,the closure prosthesis 100 may include any number of projections 112,arranged over all or part of the closure prosthesis 100, including bothfirst and second portions 102, 104 and connecting portion 106.Projections 112 can also be arranged in different planes.

Depending on the particular characteristics of pointed end 108, thepointed end 108 may also anchor the closure prosthesis 100. For example,the relatively larger back portion 114 of the pointed end 108 may alsohelp to anchor the first portion 102 of closure prosthesis 100.

The second portion 104 of closure prosthesis 100 is relatively smoothalong its length and includes an end 116 that extends substantiallytransversely to the second portion 104. For ease and clarity indescription, the first and second portions 102, 104 may be referred toas “barbed portion 102” and “T-portion 104,” which should be understoodas being equivalent in meaning to the first and second portions 102,104, respectively.

Central portion 106 of closure prosthesis 100 extends between first endportion 102 and second end portion 104 and connects first end portion102 with second end portion 104. In some embodiments, central portion106 is generally arcuate in shape with a generally circularcross-section, as shown in the embodiment of FIG. 6, although centralportion 106 may also be any other shape (e.g., more rectangular, moreoval, or more flat in cross-section) in other embodiments.

Closure prosthesis 100 may be made of a variety of materials, althoughit may be preferable to make the closure prosthesis 100 using abiocompatible material that is sufficiently rigid to hold a cut orincision in an intervertebral disc closed, yet sufficiently compliant soas to avoid further damaging the intervertebral disc should slightrelative motion between the disc and closure prosthesis 100 occur.Examples of suitable materials include nylon, prolene, dacron, ultrahigh molecular weight polyethylene (UHMWPE), and other suitable suturematerials.

In some embodiments, the closure prosthesis 100 may be formed of abioabsorbable polymer that is gradually absorbed by the body. Someexamples of suitable bioabsorbable materials are: poly L-lactic acid(PLLA), polyglycolic acid (PGA). Closure prosthesis can also be formedof other possible materials, including polytetrafluorethylene (PTFE),polyaryletherketone (PAEK), polyetheretherketone (PEEK),polyoxymethylene (acetal), polycarbonate, polysulfone, siliconeelastomers, commercially pure titanium, titanium alloys, CoCr alloys,nickel titanium (nitinol) alloys and implant grade stainless steels.

The closure prosthesis 100 may be made in a variety of shapes, asappropriate for different size incisions, cuts, and holes. These holescan vary from about 3-4 mm to 3-4 cm. Additionally, although FIG. 6illustrates an embodiment of the closure prosthesis 100 in which boththe barbed portion 102 and the T-portion 104 are of roughly equal size,one portion 102, 104 may be relatively enlarged with respect to theother portions. For example, it may be desirable to make one end portion102, 104 larger if needed to provide better anchoring to close a largercut, or a cut of a particular shape. Additional embodiments of theclosure prosthesis will be described below with respect to FIGS. 37 and38.

A user may install closure prosthesis 100 during a surgical procedure torepair intervertebral disc damage by manually inserting it, with orwithout the help of additional tools, as shown in FIGS. 4 and 5.However, a deployment device may also be used to install closureprosthesis 100. Closure prosthesis 100 can also be used to repairtendons, muscles, fascia, bone, cartilage, meniscus, ligaments or skin.

FIG. 7 is a perspective view of one embodiment of a deployment device700 that is adapted to install closure prosthesis 100. Deployment device700 in combination with prosthesis 100 may be referred to as a system.Deployment device 700 includes a body that contains a number of elementsthat assist in inserting and installing closure prosthesis 100.Preferably, deployment device 700 includes provisions to move closureprosthesis 100 into position, and provisions that associate one or moreend portions of closure prosthesis 100 with disc 202. In someembodiments, deployment device 700 is configured for one-handedoperation so that all of the various functions can be controlled withone hand and closure prosthesis 100 can be associated with disc 202using a single hand.

In an exemplary embodiment, the distal end of body 702 is coupled to acanula 703. The lumen 705 of the canula 703 can be configured to carryclosure prosthesis 100, along with provisions that help to insert andinstall it. The installation of closure prosthesis 100 and itsarrangement within the lumen 705 of the canula 703 will be described ingreater detail below. The body 702 can include a number of windows orcutouts 750 that allow a user to verify the position of the componentsthat install closure prosthesis 100.

Preferably, the provisions in the deployment device 700 for insertingand/or deploying closure prosthesis 100 include provisions for moving oradvancing one or both of barbed portion 102 and T-portion 104 of theclosure prosthesis 100, either simultaneously or differentially, so asto cause closure prosthesis 100 to span a cut, tear, hole, incision orflaw 204.

FIG. 8 is a cut-away perspective view of one embodiment of deploymentdevice 700, illustrating its components. The deployment device 700includes a first trigger 704 and a second trigger 706. In the embodimentof FIG. 8, first trigger 704 is attached to body 702 via first pivot pin708. Pivot pin 708 allows the first trigger 704 to pivot or rotaterelative to the body 702. The second trigger 706 is also designed topivot or rotate relative to body 702. As shown, the second trigger 706is coupled to the body 702 via a second pivot pin 710. Given thisconfiguration, the second trigger 706 rotates about the body 702 at thesecond pivot pin 710.

The deployment device 700 is designed to be easily held, handled andused by a user. To that end, the deployment device 700 includes ahandgrip portion 712 and a thumbrest 714. The handgrip portion 712 andthe thumbrest 714 are designed to accommodate either the left or righthand of a user. In some cases, a user's hand might engage the handgripportion 712 and use the palm and fingers to move or actuate the secondtrigger 706. One of the user's fingers can be used to actuate or movethe first trigger 704. In the embodiment of FIG. 8, first trigger 704 isdesigned as a loop and includes a hole 740, although otherconfigurations are possible and may be used to improve the ergonomics oruser comfort of the deployment device 700. Preferably, first trigger 704operates independently from second trigger 706. As shown, the handgripportion 712, the first and second triggers 704, 706, and any otherportion of the body may be knurled or otherwise surface-modified toimprove grip or traction. A variety of different materials, coatingsand/or surface treatments can be used on either or both triggers toimprove grip and prevent slipping.

Preferably, the provisions for moving or advancing one or both of barbedportion 102 and T-portion 104 of the closure prosthesis are provisionsthat convert the rotational/pivotal movement of the first trigger 704and/or the second trigger 706 into linear motion that results in thedeployment of closure prosthesis 100. In some embodiments, theprovisions for moving or advancing barbed portion 102 and T-portion 104may move or advance those portions in one-to-one correspondence with theamount of motion or pressure imparted to the first and second triggers704, 706 by the user. However, in other embodiments, the couplingbetween the first and second triggers 704, 706 may be more indirect, andthe motion of barbed portion 102 and T-portion 104 may not have adirect, one-to-one correspondence with the forces or motions applied tothe first and second triggers 704, 706. More indirect coupling of themovement of the first and second triggers 704, 706 and the movement ofbarbed portion 102 and T-portion 104 may help to produce a smoothadvancement, insertion, and/or placement of closure prosthesis 100 evenif the force or movement applied to the first and second triggers 704,706 by the user is not itself smooth.

The components and functions of the deployment device 700 are betterunderstood with reference to FIG. 12, a sectional view of a vertebra 200associated with an intervertebral disc 202, showing one end of thedeployment device 700 in section, positioned to install closureprosthesis 100. In the embodiment shown in FIG. 12, the intervertebraldisc 202 has a cut 204 facing dorsally, and the user has inserted thecanula 703 of the deployment device 700 past the spinous, transverse,and mammillary processes and facet joints 206, 208, 212 of vertebra 200to reach a location proximate to cut 204. Canula 703 may be of anylength necessary to achieve proper positioning for installation ofclosure prosthesis 100. Additionally, although the features andproportions shown in FIG. 12 and in other figures are those of humananatomy, closure prosthesis 100 and deployment device 700 may be used onany mammal.

As shown in FIGS. 7 and 12, the lumen 705 of canula 703 contains firstand second penetrating members 802, 806. Preferably, first penetratingmember 802 is configured to retain one end portion of closure prosthesis100 and second penetrating member 806 is configured to retain the otherend portion of closure prosthesis 100 prior to deployment. In someembodiments, first and second penetrating members 802 and 806 aregenerally hollow with forward penetrating tips 809 and 812,repsectively. In some embodiments, forward penetrating tips 809 and 812are designed to act as cutting needles, tapered needles or any othersuitable needle design. Preferably, each penetrating member 802, 806 hasan open channel 810, 811 formed along its inner face and an associatedhole. Although the preferred embodiment includes holes oriented inwards,the holes can be oriented in other directions as well.

Closure prosthesis 100 is preferably mounted so that the pointed end 108is disposed within the second penetrating member 806, and portions ofbarbed portion 102 protrude out of second channel 811. Preferably,transverse end 116 is within the first penetrating member 802, and thebarbed portion 102 and the T-portion 104 extend out of the respectivechannels 810, 811 in the penetrating members 802, 806 such that thecentral connecting portion 106 extends between the two penetratingmembers 802, 806. First and second push rods 804, 808 are also arrangedwithin the first and second penetrating members 802, 806.

In some embodiments, first push rod 804 is slightly longer than thesecond push rod 808, such that in the view of FIG. 12, before thedeployment device 700 is actuated to deploy the closure prosthesis 100,first push rod 804 extends farther than the second push rod 808 and canbe in contact with the transverse end 116. In some embodiments, thedistal end of the second push rod 808 is initially positioned somedistance back from the barbed portion 102. The push rods 804, 808 aregenerally coaxial with penetrating members 802, 806.

As will be explained below in greater detail, in one embodiment,actuation of the first trigger 704 forces the penetrating members 802,806 into the intervertebral disc 202 proximate to the cut 204. Actuationof the second trigger 706 causes the push rods 804, 808 to force theprosthesis 100 out of the penetrating members 802, 806 and into positionin the intervertebral disc 202.

In this embodiment, the length differential of the first and second pushrods 804, 808, in combination with other features and provisions indeployment device 700, typically causes the T-portion 104 to be deployedbefore the barbed portion 102, although this need not be the case in allembodiments. This will be explained below in greater detail.

The opposite ends of the penetrating members 802, 806 and the push rods804, 808 extend rearwardly through the lumen 705 of the canula 703 andare received in the body 702 of deployment device 700, as shown in FIG.8. The first and second penetrating members 802, 806 terminate at andare coupled to respective first and second penetration member actuators716, 718. The penetration actuators 716, 718 can be generallyrectangular blocks that are slidably mounted within body 702.Preferably, each of the first and second penetration actuators 716, 718includes a guide groove 726, 728 formed in an outward face of thepenetration actuator 716, 718. A guide rib 730 fixed with respect tobody 702 is received in each of the guide grooves 726, 728. Thisarrangement helps to secure each of the penetration actuators 716, 718to body 702 and also allow for sliding movement along the guide ribs730. In FIG. 8, only the guide rib 730 associated with the secondactuator 718 is shown; another guide rib (not shown) engages firstactuator 716 in a same manner. The first and second penetrationactuators 716, 718 may be made of a plastic or of another material witha low coefficient of sliding friction in order to minimize both wear andresistance to movement.

Each of the first and second actuators 716, 718 also includes a maingroove 720, 722. Preferably, main groove 720, 722 is disposed on a faceopposite from guide groove 726, 728. In operation, the actuators 716,718 are positioned in alignment with each other, as shown in FIG. 8, anda single push member 724 coupled to first trigger 704 is received inmain grooves 720, 722. By engaging main grooves 720, 722, push member724 is able to drive actuators 716, 718 in simultaneous sliding movementalong the respective guide ribs 730. Because the push member 724 iscoupled to the first trigger 704, a pivotal rearward movement of thefirst trigger 704 about the pivot pin 708 (clockwise rotation in FIG. 8)causes a simultaneous and coinciding forward movement of the actuators716, 718 in the distal direction, thereby forcing the respectivepenetrating members 802, 806 forward. In some embodiments, the pushmember 724 and the first trigger 704 may be formed integrally.

FIGS. 19-21 are cut-away perspective views of the forward end ofdeployment device 700, illustrating the manner of engagement of the pushmember 724 and the main grooves 720, 722 in various operationalpositions. Although only main groove 722 is shown in FIGS. 19-21, themotion and manner of engagement may be assumed to be identical for theother main groove 720. As shown, the push member 724 terminates in aslider 725 that moves within main groove 722 of actuator 718. In theforward-most position of the first trigger 704, illustrated in FIG. 19,the slider 725 is located substantially at the bottom of the main groove722. At this trigger position, actuator 718 is at a rearward or proximalposition.

In the midway-rotated position of the first trigger 704, illustrated inFIG. 20 (and also in FIG. 8), the slider 725 has reached the top of themain groove 722. At this midway-rotated trigger position, actuator 718is at a middle or intermediate position. In the fully-rotated positionof the first trigger 704, illustrated in FIG. 21, the slider 725 is onceagain at the bottom of the main groove 722. At this fully rotatedtrigger position, actuator 718 is at a forward or distal position. Theillustrated series of movements of the slider 725 occurs because thepush member 724 is rigidly coupled to the first trigger 704, and thus,the slider 725 travels in an arc as the first trigger 704 is rotated.This rotational motion is converted into linear motion by cooperation ofpush member 724 within main groove 722, and because guide rib 730 helpsto limit the motion of actuator 718. In other embodiments, if the pushmember 724 is coupled to the first trigger 704 more indirectly (e.g., bya linkage), the structures, movements, and manner of engagement may beentirely different than those shown in FIGS. 19-21.

As shown in FIG. 8, the deployment device 700 preferably includesprovisions to help deploy closure prosthesis 100. In some embodiments,deployment device 700 includes provisions to support and guide themovement of structures that advance and deploy the closure prosthesis100. In the illustrated embodiment, the first and second push rods 804,808 extend proximally (rearward as shown in FIG. 8) out of thepenetrating members 802, 806 into body 702 of deployment device 700.Preferably, first and second push rods 804, 808 are received in andguided by first and second channels 732, 734 disposed in respectiveactuators 716, 718.

Preferably, the push rods 804, 808 move independently of the actuators716, 718, and the first and second channels 732, 734 provide support forthe push rods 804, 808 without influencing their axial movement whileproviding lateral guidance. Behind actuators 716, 718, first and secondpush rods 804, 808 terminate at and are attached to respective first andsecond sliding followers 914, 916. The followers 914, 916 are slidablymounted along the respective guide ribs 730 (the other guide rib is notshown in the Figures). Preferably, first and second sliding followers914, 916, are coupled to second trigger 706, such that rearward motionof the second trigger 706 produces forward motion of the first andsecond followers 914, 916, causing the push rods 804, 808 to moveforward, as will be explained below in greater detail.

Preferably, body 702 includes a coupling member 900 disposed behindsecond trigger 706. In some embodiments, coupling member 900 is arelatively elongate member that is mounted within the body 702 forrotation about a pivot pin 908 formed on the interior of handgripportion 712. A linking member 912 is rotatively mounted, on one end, tothe rear of the handgrip portion 712 and, at the other end, to couplingmember 900. The end of the coupling member 900 in which the linkingmember 912 is received bears against the inside of the second trigger706. A spring 910 is mounted over the linking member 912, such that thelinking member 912 acts as a spring guide. With the arrangement of thecoupling member 900, the linking member 912, and the spring 910, thesecond trigger 706 is biased forwardly when not depressed because of theforce of the spring 910 acting through the coupling member 900 on theinside of the second trigger 706.

One end of the coupling member 900 preferably includes first and secondcam surfaces 902, 904 that bear against respective first and secondbearing surfaces 950, 952 associated with respective first and secondfollowers 914, 916. Preferably, the shape and characteristics of the camsurfaces 902, 904 and, optionally, the bearing surfaces 950, 952 areadapted to produce a set of movements appropriate to deploy the closureprosthesis 100. The particular movements that the cam surfaces 902, 904and the bearing surfaces 950, 952 are adapted to produce may vary withthe application and with the type and characteristics of the closureprosthesis 100.

As shown in FIG. 8, the two cam surfaces 902, 904 are not identical,such that when the coupling member 900 is caused to rotate by relativemovement of the second trigger 706, the movement produced in the firstand second followers 914, 916 is not identical. Specifically, the firstcam surface 902 is relatively shorter in height as compared with thesecond cam surface 904, such that the first cam surface 902 bears on thefirst bearing surface 950 early in the movement cycle and then moves toa position below the first follower 914. The specific movement sequenceand potential advantages of the illustrated profiles of the first andsecond cam surfaces 902, 904 will be described below in more detail.However, in other embodiments, the two cam surfaces 902, 904 may beidentical, resulting in initial identical, simultaneous movement of thetwo followers 914, 916.

The actual profiles of the two cam surfaces 902, 904 may be determineddepending on the size of the prosthesis 100 and the amount of movementof one follower 914, 916 relative to the other follower 914, 916 that isdesired, among other factors. The profiles illustrated in FIG. 8 are butone example.

The deployment device 700 preferably also includes provisions fortemporarily fixing the position of one or more elements used to deployclosure prosthesis 100 during some or all of the deployment cycle. Inthe illustrated embodiment, the body 702 of the deployment device 700includes a locking catch mechanism generally indicated at 918. Thelocking catch mechanism 918 comprises a generally flat, relatively wideengaging member 920 that is pivotally mounted along the top of the body702 and extends downwardly, acting as a pawl. A leaf spring 922 attachedto the upward face of the engaging member 920 bears against an upperinside surface of the body 702 and biases the engaging member 920downwardly.

The first and second followers 914, 916 have respective engagingportions 924, 926 on their upward faces. Each of the first and secondengaging portions 924, 926 is adapted to engage and cooperate with theengaging member 920 of the locking catch 918. As the followers 914, 916move forward, the engaging portions 924, 926 are brought into contactwith the engaging member 920. However, the manner in which the twoengaging portions 924, 926 engage the engaging member 920 is different.Specifically, the first engaging portion 924 has engaging teeth that maylock it in place and prevent rearward movement with respect to theengaging member 920. The second engaging portion 926 is shaped such thatit provides relatively free movement past the engaging member 920. Aswill be explained below in greater detail, the first engaging portion924 may prevent the first follower 914 from moving rearwardly after thefirst cam surface 902 has moved to a downward position below the firstfollower 914 and can thus no longer prevent the first follower 914 frommoving rearwardly.

The interaction of the components described above and their relativemotions are best understood with reference to FIGS. 9-11, which show theseries of movements within the body 702 when the first and secondtriggers 704, 706 are actuated, and with respect to corresponding FIGS.22-25, which are perspective views of the first and second cam surfaces902, 904, the associated first and second followers 914, 916, and thepush rods 804, 808 in isolation, illustrating the movements specific tothose components as the second trigger 706 is actuated. In FIGS. 22-25,certain components have been omitted in order to focus on the first andsecond cam surfaces 902, 904 and the first and second followers 914,916.

In the position shown in FIG. 9, as indicated by the arrow, the firsttrigger 704 has been pushed rearwardly, causing the push member 724 tomove the actuators 716, 718 forward, which results in forward movementof the penetrating members 802, 806. In the position shown in FIG. 10,the first trigger 704 is still in its rearward, actuated position whenthe second trigger 706 is actuated and the coupling member 900 is causedto move such that the first and second cam surfaces 902, 904 and firstand second followers 914, 916 move forward. In FIG. 10, the first andsecond followers 914, 916 have reached the position of cooperating withengaging member 920 and the engaging portion 924 of the first follower914 engages the engaging member 920 to lock the first follower 914 inplace. The second follower 916, because of its non-locking engagingportion 926, is free to continue moving forward as the second trigger706 is actuated. As the motion continues, the second follower 916continues moving forward until it reaches the position illustrated inFIG. 11.

The interaction of the first and second cam surfaces 902, 904 with thefirst and second followers 914, 916 and the associated movements of thepush rods 804, 808 can be seen more clearly in FIGS. 22-25. Of thosefigures, FIG. 22 corresponds to the initial position of the deploymentdevice 700 prior to the actuation of the second trigger 706. FIG. 23corresponds generally to the position shown in FIG. 10, and FIG. 24corresponds to the position shown in FIG. 11. However, as will bereadily appreciated, FIGS. 22-25 omit certain elements, such as thelocking catch mechanism 918, in order to focus on the interaction of thefirst and second cam surfaces 902, 904 with the respective first andsecond followers 914, 916. FIG. 25 illustrates the full range of motionof the first and second followers 914, 916. In the position illustratedin FIG. 25, the first follower 914 is held in place by the action of thelocking catch mechanism 918 acting upon it and can thus remainstationary in the illustrated position as the closure prosthesis beginsto exert circumferential stress on the intervertebral disc 202. Theaction of the locking mechanism 918 prevents the T-portion 104 frombeing pulled rearwardly by the forces being applied by the secondfollower 916.

One other optional feature can be seen in FIGS. 22-25: the first andsecond bearing surfaces 950, 952 of the first and second followers 914,916 are convexly curved. The curvature of the first and second bearingsurfaces 950, 952 may allow for a smoother and more precise movement ofthe followers 914, 916, because of the smaller contact area between thefirst and second bearing surfaces 950, 952 and the respective first andsecond cam surfaces 902, 904. However, the shape of the first and secondbearing surfaces 950, 952 need not be curved in all embodiments, andinstead may be determined in accordance with the desired application anddesired extent and nature of the movements to be generated.

FIGS. 8-11 and 22-25 primarily illustrate the movements of structureswithin the deployment device 700. The corresponding motion in canula 703that installs the prosthesis 100 is illustrated in FIGS. 12-16. Theinitial position of the canula 703 in FIG. 12 (with neither one of thetriggers 704, 706 depressed) was described above. In FIG. 13, the userhas actuated the first trigger 704, causing the first and secondpenetrating members 802, 806 to penetrate the nucleus purposus 222proximate to the cut 204. Once the first trigger 704 has been actuatedand the penetrating members 802, 806 are in the position shown in FIG.13, the user can then actuate second trigger 706, which, as wasexplained above, causes a series of movements.

First, as shown in FIG. 14, the movement of the second trigger 706causes the first push rod 804, which is longer than the second push rod808, to force the T-portion 104 out of the first penetrating member 802.In some embodiments, this occurs at about the same time that the secondpush rod 808 establishes initial contact with the barbed portion 102.The arcuate end 809 of the first penetrating member directs thetransverse end 116 outward and inward, until it assumes it deployedposition generally perpendicular to the T-portion 104, as shown in FIG.15. Once the transverse end 116 is deployed, the barbed portion 102 isalso deployed by the continuing movement of the second follower 916 andthe second push rod 808. Once the closure prosthesis 100 reaches theposition illustrated in FIG. 15 and has been deployed, penetratingmembers 802 and 806 are retracted within canula 703 and the entireassembly is preferably withdrawn, as shown in FIG. 16.

The motion of closure prosthesis 100 shown in FIGS. 14 and 15 may havecertain advantages. Specifically, because the T-portion 104 is ejectedfrom the first penetrating member 802 and is deployed in theintervertebral disc 202 first, it can act as an anchor on one side ofcut or flaw 204 as barbed portion 102 is being implanted. Thisarrangement also allows T-portion 104 to begin to exert circumferentialclosing forces on the cut 204 as the barbed portion 102 begins to enterthe intervertebral disc 202. Thus, the anchoring of one portion 104before the other portion 102 may help to create the circumferentialforces that cause the cut or flaw 204 to close.

In the final position shown in FIG. 16, closure prosthesis 100preferably applies a circumferential force proximate cut or flaw 204. Insome embodiments, this circumferential force helps to close or securecut or flaw 204. T-portion 104 is inserted such that transverse end 116rests in a position generally perpendicular to the remainder of theT-portion 104. The pointed end 108 of the barbed portion 102 can also beinserted to a resting position inside the nucleus purposus 222. However,the position of FIG. 16 is not the only possible operative position forthe closure prosthesis 100. For example, the barbed portion 102 need notpenetrate all the way through the nucleus purposus 222; instead, anyamount of penetration that lodges the barbed portion 102 within thenucleus purposus 222 well enough to close the cut 204 is sufficient.

Additionally, although the cam surfaces 902, 904 and associatedstructures are adapted in the illustrated embodiment to move theT-portion 104 into the intervertebral disc 202 before the barbed portion102, this need not always be the case. In other embodiments, if the userfound it to be desirable or necessary (for example, to treat aparticular type of cut or flaw), cam surfaces 902, 904 and otherassociated structures could be configured such that the barbed portion102 is moved into the intervertebral disc 202 first. Moreover, thebarbed portion 102 and the T-portion 104 of the closure prosthesis 100could be advanced into the intervertebral disc 202 at the same time.

FIG. 16 also shows a relative spacing between the barbed portion 102 andthe T-portion 104 of the prosthesis 100 that could be adapted to meetparticular needs. For example, if a user believed that the nucleuspurposus tissue immediately proximate to the cut would not sufficientlyanchor the closure prosthesis 100, a wider closure prosthesis 100 couldbe used, such that its two portions 102, 104 are farther spaced from thecut 204.

Additionally, although a particular application in intervertebral discrepair has been illustrated and described in the foregoing, closureprosthesis 100 and delivery device 700 may be used to close cuts, tears,holes, and incisions in other types of tissue. It is also possible totreat a bulging disc with closure prosthesis 100. In these cases, aprotruding bulge or imperfection that has not yet begun to cut or tearcan be pressed back towards its original position along the nucleuspurposus.

Whatever its ultimate use or features, delivery device 700 is preferablyadapted for use in a medical environment. For example, the push rods804, 808, penetrating members 802, 806, and canula 703 may be detachablefrom their respective points of connection on the body 702 so as tofacilitate autoclaving or other sterilization procedures. Thosecomponents may also be interchangeable with rods, penetrating members,and canulas of various sizes, so as to accommodate different surgicaland repair situations. Body 702 itself may also be autoclavable orotherwise sterilizable, because the user may grasp it during a repairprocedure with a contaminated hand or glove. In some embodiments,delivery device 700 is disposable.

Some embodiments include provisions for withdrawing or retracting firstand second push rods 804 and 808. FIG. 17 is a side elevational view ofthe upper portion of the coupling member 900 showing the details of oneembodiment of a retracting mechanism. FIG. 18 is a sectional view takenthrough Line 18-18 of FIG. 17. On the side of the upper portion of thecoupling member 900 behind second cam surface 904 is a first recessedpocket 928. A pin 934 that is formed integrally with the inside face ofthe second follower 916 extends into and cooperates with the firstrecessed pocket 928. The cooperation of the pin 934 with the pocket 928couples the motion of the coupling member 900 and the motion of thesecond follower 916.

The motion of first follower 914 and second follower 916 is alsopreferably associated. Farther forward on the inward face of the secondfollower 916 is a second recessed pocket 956. A projection 932 on theinward face of first follower 914 is preferably disposed in secondrecessed pocket 956. As will be appreciated from FIG. 18, the couplingof the first and second followers 914, 916 and the correspondingcoupling of the coupling member 900 and the second follower 916 allowsrelatively free and independent movement of the various componentswithin their normal deployment range of motion. At the same time, thevarious mechanical associations help to retract first and second pushrods 804, 808 when the motion of coupling member 900 is reversed.

Referring to FIGS. 8-11, 17 and 18, when the second trigger 706 isreleased, the cam spring 910, acting through the coupling member 900,biases second trigger 706 back to its original position, shown in FIG.8. Simultaneously, as the force of the cam spring 910 acting on thecoupling member 900 causes the coupling member 900 to rotatecounterclockwise, the rotation of the coupling member 900 moves thefirst and second cam surfaces 902, 904 rearwardly. When this occurs, aninterior bearing surface 954 of the first recessed pocket 928 bearsagainst the pin 934, forcing the second follower 916 to move rearwardlyas well. Meanwhile, at the forward end of the second follower 916, aninterior bearing surface 958 of the second recessed pocket 956 bearsagainst the projection 932, forcing the first follower 914 to moverearwardly as the second follower 916 moves rearwardly. Additionally, asthe second follower 916 travels rearwardly, the ramp shape of itsengaging portion 926 lifts the engaging member 920 off of the toothedengaging portion 924 of the first follower 914, thus clearing engagingmember 920 from engaging portion 924 of first follower 914, and allowingfirst follower 914 to move.

As mentioned above, the particular features of the components indeployment device 700 may be selected and adapted to carry out whateverkind of deployment sequence and/or movements are necessary or desired toplace the closure prosthesis. In the embodiment described above andillustrated in FIGS. 8-25, cam surfaces are illustrated, the first camsurface 902 is shortened in height, and the first push rod 804 islengthened in order to produce a deployment movement sequence thatdeploys the T-portion 104 of the closure first. Other cam profiles andcomponent features may also be chosen.

For example, FIGS. 26-29 are perspective views of the upper terminalportion of a coupling member 900′ according to another embodiment. Thecoupling member 900′ carries first and second cam surfaces 902′, 904′,which cooperate with first and second followers 914′, 916′ and bearagainst first and second bearing surfaces 950′, 952′ on the respectivefirst and second followers 914′, 916′. The first and second followers914′, 916′ are coupled to first and second push rods 804′, 808′ which,in this embodiment, have lengths that are substantially identical. Theother components of a deployment device that includes the structuresshown in FIGS. 26-29 may be assumed to be similar to those shown anddescribed with respect to deployment device 700, although somecomponents may be adapted as necessary to function with coupling member900′.

In the embodiment of FIGS. 26-29, a differential movement is producedthat deploys the T-portion 104 of the closure prosthesis 100 into thetissue first, like in the previous embodiment. However, the differentialmovement used to deploy the T-portion 104 before the barbed portion 102is produced by selecting different cam profiles for the first and secondcam surfaces 902′, 904′. In some embodiments, this cam profiledifference can be used in conjunction with first and second push rods804′, 808′ that have generally similar lengths.

More particularly, as will be appreciated from FIG. 26, the first camsurface 902′ is initially positioned in contact with the bearing surface950′ of the first follower 914′. However, the profile of the second camsurface 904′ is different and swept back and relatively offset withrespect to the first cam surface 902′; thus, the second cam surface 904′does not initially make contact with the bearing surface 952′ of thesecond follower 916′. FIG. 27 shows the initial portion of the movement,during which the first follower 914′ advances forward. In the positionillustrated in FIG. 27, the second cam surface 904′ has just madecontact with the bearing surface 952′ of the second follower 916′. Asshown in FIG. 28, the first cam surface 902′ reaches its upper extentand begins to rotate under the first follower 914′ when the secondfollower 916′ is in mid-advance. Eventually, the two first and secondfollowers 914′, 916′ reach the same end position, as shown in FIG. 29.

Although the two embodiments described in detail illustrate the use ofsimilar and dissimilar cam surfaces, it should be appreciated that otherlinear motion-producing mechanisms may be used within deployment device700. For example, in alternative embodiments, linkages, gearing, orother linear motion mechanisms could be coupled to the second trigger toproduce the desired movements.

Closure prosthesis 100 may be used in a variety of different types ofprocedures to close a cut, tear, incision, hole, or flaw 204 in anintervertebral disc 202, with or without a deployment device such asdeployment device 700. Also, the use of closure prosthesis 100 is notnecessarily limited to intervertebal discs. As mentioned above, closureprosthesis 100 can be used to repair tendons, muscles, fascia, bone,cartilage, ligaments or skin in other parts of an organism besides theintervertebal disc region.

More particularly, as was described briefly above, when anintervertebral disc 202 becomes herniated or ruptures because of trauma,the cut, tear, incision, hole, or flaw 204 may have any initial shape,and may also have ragged edges. In order to allow for better closure,and to promote better healing, the operating surgeon or other medicalpractitioner may make an incision of a particular shape and then use oneor more closure prostheses 100 to close the incision.

FIG. 30 is a perspective view of a single vertebra 200 and itsassociated intervertebral disc 202, illustrating a box-shaped incision3002 in the intervertebral disc 202. The box-shaped incision 204 isformed by cutting a rectangular area out of the nucleus purposus 222.The nucleus purposus 222 is then closed, as shown in FIG. 31, by a firstclosure prosthesis 100 that spans the box-shaped incision 3002circumferentially (horizontally in FIG. 31). As shown schematically inFIG. 31, first closure prosthesis can provide a hoop stress tointervertebral disc 202. This hoop stress can also be thought ofproviding a cinching force about the circumference, either locally orthroughout the entire circumference, of intervertebral disc 202. In somecases, this hoop stress helps to axially expand intervertebral disc 202.In other words, the application of circumferential force can help toincrease the height (the vertical dimension as shown in FIG. 31) ofintervertebral disc 202. In some cases, this axial expansion orincreased height is noticeable, and in other cases, this axial expansionor height increase is very slight and difficult to notice. In stillother cases, the axial expansion or height increase of intervertebraldisc 202 caused by the hoop stress is prevented or restrained by otherforces and/or anatomical features that compress the spinal column.

In some embodiments, an optional second closure prosthesis 3202 can beused. In some cases, second closure prosthesis 3202 is disposed at anangle different than the position of first closure prosthesis 100. In anexemplary embodiment shown in FIG. 32, second closure prosthesis 3202 isdisposed substantially normal to first closure prosthesis 100. In theembodiment shown in FIG. 32, second closure prosthesis 3202 is disposedaxially (vertically as shown in FIG. 32) across incision 3002. Beforeclosing the incision 3002, a portion of the volume once occupied by thenucleus purposus 224 in the intervertebral disc 202 may be re-filledwith a biocompatible polymer of appropriate mechanical properties so asto improve the elastic response of the intervertebral disc 202. Someexamples of suitable biocompatible polymers that can be used to re-fillthe volume of the nucleus purposus 224 include: dacron mesh, siliconeelastomers, hydrogel, and commercially available nucleus replacements.Other materials can be used as well.

FIG. 33 is another perspective view of a single vertebra 200 and itsassociated intervertebral disc 202, illustrating an X-shaped incision3302 in the intervertebral disc 202. The X-shaped incision 3302 isformed by making two crossed incisions in the nucleus purposus 222. Theangular orientation of X-shaped incision 3302 can be varied. A typicalX-shaped incision 3302, where the two cuts that form the incision areangled with respect to the circumferential and axial directions, isshown in FIG. 32. In some cases, an X-shaped incision is made where thetwo cuts are generally aligned with the circumferential and axialdirections. In these cases, the X-shaped incision would feature agenerally vertical cut and a generally horizontal cut in intervertebraldisc 202 as shown in FIG. 32.

Preferably, X-shaped incision 3302 in nucleus purposus 222 is closed, asshown in FIG. 34, by first closure prosthesis 100 that spans theX-shaped incision 3302 in a first direction. Preferably, first closureprosthesis 100 is disposed in a generally circumferential direction(horizontally in FIG. 34) across X-shaped incision 3302. As shownschematically in FIG. 34, first closure prosthesis 100 can provide ahoop stress to intervertebral disc 202. This hoop stress can also bethought of providing a cinching force about the circumference, eitherlocally or throughout the entire circumference, of intervertebral disc202. In some cases, this hoop stress helps to axially expandintervertebral disc 202. In other words, the application ofcircumferential force can help to increase the height (the verticaldimension as shown in FIG. 34) of intervertebral disc 202. In somecases, this axial expansion or increased height is noticeable, and inother cases, this axial expansion or height increase is very slight anddifficult to notice. In still other cases, the axial expansion or heightincrease of intervertebral disc 202 caused by the hoop stress isprevented or restrained by other forces and/or anatomical features thatcompress the spinal column.

In some embodiments, an optional second closure prosthesis 3502 can beused. In some cases, second closure prosthesis 3502 is disposed at anangle different than the position of first closure prosthesis 100. In anexemplary embodiment shown in FIG. 35, second closure prosthesis 3502 isdisposed substantially normal to first closure prosthesis 100. In theembodiment shown in FIG. 35, second closure prosthesis 3202 is disposedaxially (vertically as shown in FIG. 35) across incision 3302. Beforeclosing the incision 3302, a portion of the volume once occupied by thenucleus purposus 224 in the intervertebral disc 202 may be re-filledwith a biocompatible polymer of appropriate mechanical properties so asto improve the elastic response of the intervertebral disc 202.

FIG. 36 is another perspective view of a single vertebra 200 and itsassociated intervertebral disc 202, illustrating a tall verticalincision 3602 in the nucleus purposus 222 that has been closed by twoclosure prostheses 100 both generally circumferentially disposed(horizontally as shown in FIG. 36) on intervertebral disc 202.

As shown schematically in FIG. 36, first closure prosthesis 100 canprovide a hoop stress to intervertebral disc 202. This hoop stress canalso be thought of providing a cinching force about the circumference,either locally or throughout the entire circumference, of intervertebraldisc 202. In some cases, this hoop stress helps to axially expandintervertebral disc 202. In other words, the application ofcircumferential force can help to increase the height (the verticaldimension as shown in FIG. 36) of intervertebral disc 202. In somecases, this axial expansion or increased height is noticeable, and inother cases, this axial expansion or height increase is very slight anddifficult to notice. In still other cases, the axial expansion or heightincrease of intervertebral disc 202 caused by the hoop stress isprevented or restrained by other forces and/or anatomical features thatcompress the spinal column.

As shown in FIG. 36, depending on the nature of the incision, it may notbe necessary to provide a closure prosthesis with a different angularorientation. Although FIG. 36 shows a generally axial orientation(vertical in FIG. 36) of incision 3602, it is also possible thatincision 3602 be angled with respect to the particular incision 3602shown in FIG. 36. In other embodiments, it is possible to provide morethan two closure prosthesis in similar or different angular orientationswith respect to an incision.

Although surgical and prosthesis deployment methods may vary with thepatient's particular diagnosis or injury, as well as at the discretionof the operating surgeon, placing a horizontal closure prosthesis 100first may help to provide the circumferential stress to close theintervertebral disc 202, and may also help to increase the axial heightof the intervertebral disc 202. Additionally, although two closureprostheses 100 have been used to close some of the incisions shown inthe previous figures, any number of closure prostheses 100 may be used,and the closure prostheses 100 that are used may be of any size.

As was noted above, the closure prosthesis 100 may also be varied in anumber of ways for different applications. For example, FIG. 37illustrates an embodiment of a closure prosthesis 100′ that has twobarbed portions 102 and no T-portion 104. The structure of closureprosthesis 100′ is otherwise generally similar to that of closureprosthesis 100.

FIG. 38 illustrates an embodiment of a closure prosthesis 100″ that hastwo T-portions 104 and no barbed portion 102. The structure of closureprosthesis 100″ is otherwise generally similar to that of closureprosthesis 100.

While various embodiments of the invention have been described, thedescription is intended to be exemplary, rather than limiting and itwill be apparent to those of ordinary skill in the art that many moreembodiments and implementations are possible that are within the scopeof the invention. Accordingly, the invention is not to be restrictedexcept in light of the attached claims and their equivalents. Also,various modifications and changes may be made within the scope of theattached claims.

1. A method for repairing an imperfection on a disc associated with aspinal column comprising the steps of: inserting a first end portion ofa prosthesis into a first portion of the disc, wherein the first portionof the disc is on a first side of the cut; the prosthesis having acentral portion connected to the first end portion and a second endportion connected to the central portion; the first end portion having afirst anchoring device, and the second end portion having a secondanchoring device; inserting the second end portion of the prosthesisinto a second portion of the disc that is circumferentially spaced fromthe first portion of the disc, and wherein the second portion of thedisc is on a second side of the imperfection; and spanning theimperfection with the central portion of the prosthesis.
 2. The methodaccording to claim 1, wherein the second end portion of the prosthesisis further inserted into the disc thereby drawing the first side of theimperfection closer to the second side of the imperfection.
 3. Themethod according to claim 1, wherein the first anchor includes at leastone projection extending away from the first end portion.
 4. The methodaccording to claim 1, wherein the second anchor includes at least onebarb.
 5. The method according to claim 1, wherein the prosthesis in aninstalled position provides a circumferential force on the disc.
 6. Themethod according to claim 1, wherein the prosthesis provides a hoopstress on the disc.
 7. The method according to claim 1, wherein theprosthesis helps to maintain the axial height of the disc.
 8. The methodaccording to claim 1, wherein the prosthesis helps to increase the axialheight of the disc.
 9. The method according to claim 1, wherein theprosthesis helps to close the imperfection on the disc.
 10. The methodaccording to claim 1, wherein the prosthesis helps to retain discnucleus material within the disc.
 11. The method according to claim 1,wherein the imperfection is a bulge on the disc.
 12. The methodaccording to claim 1, wherein the imperfection is a hole in the disc.13. The method according to claim 1, wherein the imperfection is anintentional cut hole on the disc.
 14. The method according to claim 1,wherein the imperfection is a tear on the disc.
 15. The method accordingto claim 1, wherein the first anchoring device is generally T-shaped.16. The method according to claim 1, wherein the first anchoring deviceincludes at least one barb.
 17. The method according to claim 1, whereinthe second anchoring device includes at least one barb.
 18. The methodaccording to claim 1, wherein the second anchoring device is T-shaped.19. The method according to claim 1, wherein the first anchoring deviceis T-shaped and the second anchoring device is T-shaped.
 20. The methodaccording to claim 1, wherein the first anchoring device includes atleast one barb and the second anchoring device includes at least onebarb. 21-62. (canceled)